FIG. 1 illustrates a block diagram of a basic N-bit analog-to-digital converter. The analog input signal is designated as Vin*. The input, along with a reference voltage Vref, is used to determine the digital output that best represents the analog input signal. In the figure, a set of fixed reference levels Vi are applied to comparators whose outputs Xi are then decoded into an output digital signal. The A/D converter converts a continuous range of input amplitude levels into a discrete set of digital signals. FIG. 2 illustrates an ideal input-output characteristic for a 3-bit A/D converter.
However, there is 1-bit jitter or oscillation in the output signal when the analog input signal has noise and/or the digital signal is on the edge of an increasing or decreasing bit. It is difficult to remove this oscillation without sacrificing the conversion resolution or increasing the total number of bits of the output digital signal.